Former LSU football players Zach Mettenberger and Anthony Johnson had their drug tests flagged at the NFL combine, according to multiple reports Monday.

Mettenberger had a diluted sample, which constitutes a failed drug test. Johnson, a defensive tackle projected as a midround selection, failed his test, Fox Sports reported.

No traces of illegal or banned substances were found in Mettenberger’s sample, the quarterback’s agent, Seth Katz, told The Advocate on Monday night. The sample was diluted by extra water that the quarterback was drinking on the advice of his trainer, Katz said.

“This is not a big deal,” Katz said. “He had too much water in his (specimen).”

Mettenberger is projected as a second- or third-round selection in the draft, which begins Thursday.

“Teams that we have spoken to have each assured us they understand and are not concerned by this,” Katz said.

The combine was Feb. 19-25, about eight weeks after Mettenberger had surgery to repair a torn ACL. During intense rehabilitation, Mettenberger began to experience severe muscle cramping and dehydration, according to the player’s trainer, Jason Eliowitz. Eliowitz advised Mettenberger to drink 1 to 1.5 gallons of water a day, to increase his consumption of foods high in potassium, and to increase his sodium intake.

Eliowitz sent a letter to Lawrence Brown, the NFL’s independent advisor and consultant of drugs of abuse, explaining the situation. Brown conducted the drug tests at the combine. A copy of the letter was provided to The Advocate.

“The high consumption of fluid was necessary to counteract the dehydration for intense training sessions and to promote a healthy fluid balance,” Eliowitz wrote to Brown.

Brown sent Mettenberger a document detailing the diluted sample. Katz said he has been unable to reach Brown to get clearance to release that document.

The document from Brown, Katz said, informs Mettenberger that he was flagged for producing a diluted specimen, and “It does not reference any traces of illegal of banned substances.”